1. Field of the Invention
The present invention relates to a digital signal transmission cable and a digital video display system that uses the digital signal transmission cable.
2. Description of the Background Arts
With the marked popularity of personal computers and liquid crystal displays, the number of image transmission technologies employing digital signals instead of conventional analog signals has increased. One of the newer digital signal technologies is the digital visual interface (DVI). Currently, the scope of use of DVI technology and products and devices that utilize DVI technology are being developed. Digital signal transmission cables employing DVI technology include metal wire cables that have a transmission range of several meters or optical fiber cables that eliminate the transmission range limitations of metal wires and can transmit over large distances (e.g., see Japanese Published Unexamined Patent Application No. 2002-366340).
Digital signal transmission cables employing DVI technology are used chiefly to connect personal computers to display devices and projectors. Until recently, a problem of signal degradation resulting from the distance of transmission and the existence of intermediate connection components was not particularly large because the devices were seldom placed far apart from each other. However, in recent years the environments in which digital images are displayed have changed greatly. The locations from which images are displayed have become more diverse, e.g., the showing of movies and other video footage in large venues and the displaying of advertisements using wall-mounted displays, and it has become necessary to arrange image output devices in positions that are remote from the positions of image input devices. Furthermore, unlike the past when computer screens were used to display chiefly text, computers are now used for displaying photographs, viewing moving pictures (e.g., video), and other applications that demand higher image quality. Consequently, issue of preventing signal degradation has become extremely important.
As compensation technologies related to DVI technology, technologies for shaping and amplifying transmitted signals have been developed as device components. These compensation technologies have typically involved shaping a signal that has propagated along a digital signal transmission cable and then amplifying the signal with an amplification circuit. As DVI specification itself spreads, dedicated LSI circuits (IC chips) were developed to support DVI. One such LSI circuit is the MAX3815 made by the U.S.-based company Maxim Integrated Products, Inc. However, the MAX3815 is designed solely to be installed inside a projector or other image output device. Consequently, it is not preferable in view of preventing signal degradation to use a projector, liquid crystal display, or other image output device that is not provided with such an LSI chip when such projector, liquid crystal display, or other image output device is positioned distantly with respect to the personal computer, the digital virtual disk (DVD) player or other image input device.